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Investigation of megakaryocyte apoptosis in children with acute and chronic idiopathic thrombocytopenic purpura.

Abstract: Objective: Although the platelet destruction shows a primary role in the thrombocytopenia of idiopathic thrombocytopenic purpura (ITP), it has been demonstrated that impaired platelet production may also contribute to the severity of thrombocytopenia in ITP. The present study examined megakaryocyte apoptosis in bone marrow aspirates of children with acute and chronic ITP and investigated the role of megakaryocyte apoptosis in ITP pathophysiology.

Autoimmune lymphoproliferative syndrome: report of two cases and review of the literature

Abstract. Autoimmune lymphoproliferative syndrome (ALPS) is a rare disease occurring in childhood. Recently, it has been shown that heritable mutations in Fas or Fas ligand genes, which regulate lymphocyte survival by triggering apoptosis of lymphocytes, are the most frequent cause of ALPS. Patients with ALPS frequently have lymphadenopathy, splenomegaly and hepatomegaly, especially at young ages. A positive result of the Direct Coombs test, autoimmune hemolytic anemia, and idiopathic thrombocytopenic purpura are the most common features of autoimmunity in patients with ALPS. Elevated numbers and percentages (>1%) of double-negative (CD4–CD8–) T cells, and characteristic pathologic findings in lymph nodes or spleen are other important diagnostic features. In this report, we present the clinical, immunologic, and pathologic features of two children who were diagnosed with ALPS. The early recognition of ALPS in children with enlarged lymph nodes, hepatosplenomegaly, and autoimmune hematologic features has important diagnostic and prognostic value in avoiding expensive and time-consuming studies and unnecessary treatments. The ratio of CD4–CD8– T cells, immunoglobulin levels and the histopathologic features of lymph nodes should be rapidly determined in these patients in order to establish an early diagnosis and treatment.

A pediatric case of lymphomatoid granulomatosis with onset after completion of chemotherapy for acute myeloid leukemia

In this case report, we present a pediatric case of lymphomatoid granulomatosis (LG) with onset just after the completion of chemotherapy for childhood acute myeloid leukemia (AML). After the completion of maintenance therapy, the patient was admitted to our clinic with a complaint of cough. Radiologic examinations revealed nodular lesions in lungs, liver, and kidney. His bone marrow was in remission. The histopathologic examination of the open lung biopsy was consistent with LG. He received only one cycle of cyclophosphamide and high-dose methyl prednisolone treatment and continued to receive interferon (IFN) alpha-2b therapy for 18 months. This treatment regimen resulted in an excellent response. In conclusion, LG may occur after the treatment of pediatric AML as a rare complication and IFN alpha-2b may be an effective treatment choice in these patients.

Plasma transforming growth factor β1 levels in thrombocytopenic and nonthrombocytopenic neonates

In this study, we determined the plasma TGF-β1 levels in healthy and thrombocytopenic and nonthrombocytopenic neonates who had perinatal risk factors and examined the association between plasma TGF-β1 levels and platelet counts in these newborns to investigate the role of TGF-β1 in the pathogenesis of neonatal thrombocytopenia. Three groups were defined in this prospective study: group 1, thrombocytopenic neonates (n = 22) who had perinatal risk factors; group 2, nonthrombocytopenic neonates who had similar perinatal risk factors for thrombocytopenia (n = 20); group 3, healthy and nonthrombocytopenic neonates without any risk factors (n = 20). Plasma TGF-β1 levels were measured with ELISA. Plasma TGF-β1 levels of the thrombocytopenic neonates were significantly lower than those of healthy nonthrombocytopenic neonates but did not differ significantly from nonthrombocytopenic neonates who had similar perinatal risk factors for thrombocytopenia. There was a significant positive correlation between plasma TGF-β1 levels and platelet counts. Further studies are needed to determine the cause of low plasma TGF-β1 levels in thrombocytopenic neonates and to investigate the role of plasma TGF-β1 levels in the pathogenesis of neonatal thrombocytopenia.